Masking of cyan images in color photography



3,028,237 Patented Apr. 3, 1962 thee 3,028,237 MASKING F CYAN IMAGES IN(101.011 PHQTOGRAPHY Karl Loitler, Leverkusen, Germany, assignor to AgraAlrtiengesellschaft, Leverkusen, Germany, a corporation of Germany NoDrawing. Filed Apr. 8, 1958, Ser. No. 727,043 Claims priority,application Germany Apr. 25, 1%7 8 Claims. (Cl. 96-9) The presentinvention relates to a process and to materials for producing cyanimages which are combined with red masking images.

For improving the color reproduction when the subtractive color processis used, it is known to employ colored masks which have a gradationopposite to that of the partial image to be masked and absorb in therange of unwanted secondary color density in the partial image dyestutf.In practice yellow masks are most frequently used for masking themagenta dyestuff, and red masks are used for correcting the secondarycolor densities of the cyan-dyestuffs.

In the case where the colored correcting masks are not on a separatesupport but in a multi-layer material that includes the image to bemasked, two fundamental principles have been proposed for preparing themasks:

(1) Conversion of the residual color coupler after color development ofthe primary image into a colored correcting image by subsequenttreatment with solutions of suitable diazonium compounds or aldehydes,for example.

An obvious disadvantage of this process is the increased complication ofthe processing and the increased likelihood of defective results whichis connected therewith,

as well as in the difiiculty of excluding an analogous but undesiredcolor reaction with the yellow coupler.

(2) Recoupling of colored color couplers already in the layer by colordevelopment to give image dyestufis, that portion which is not recoupledremaining as a colored mask.

An essential disadvantage of the recoupling process is that the layerswhich are dyed from the outset lower the light sensitivity of the silverhalide. This is especially so when interchange of the layers, desirablefor other reasons, is carried out, for example where a red-dyed layerfor masking the cyan image is arranged above the greensensitive layer.

It has now been found that a red masking image for the cyan partialimage can be obtained in a very simple manner and without thedisadvantages referred to if one or more diaminesof the general formulaare incorporated into the layer along with the cyan coupler, R in thisgeneral formula representing a straight or branched chain alkyl radical,for example with at least 6, preferably 10 to carbon atoms and Rrepresenting a solubilizing group, for example a sulfonic acid orcarboxyl group. Orthodiamines of this type are inert with respect to thecolor developing bath but in a subsequent silver bleaching bath, forexample with potassium ferricyanide, undergo an oxidizing reaction withthe residual cyan coupler to give red dyestufis, so that, during theconventional processing and without additional measures or baths beingnecessary, a red correcting image is formed with a gradation opposite tothat of the cyan image, that is to say a positive red masking image incase that the cyan image is negative and a negative red masking image incase that the cyan image is positive. In accordance with the invention,the optimal density of the red masking image can easily be obtained byadding an appropriate proportion of the diamine to the silver halideemulsion layer, whereas this is not readily possible when coloredcouplers are used. The diamines are preferably applied in amounts of 1-6g. and the cyan color coupler in amounts of 520 g. per 1 kg. of silverhalide emulsion.

Examples of suitable diamines are:

4-octadecylamino-3-aminobenzene sulphonic acid,4-octadecylamino-3-aminobenzoic acid, 4-dodecylamino-3-aminobenzoicacid,

The diamines can be produced in known manner by the replacement ofsubstituents, such as chlorine or bromine, in the ortho-position to thenitro group by the radical of a primary amine and subsequent reductionof the nitro group to the amino group. For example4-octadecylarnino-3-amino-benzene sulphonic acid is formed from4-chloro-3-nitrobenzene sulphonic acid by the use of stearyl amine andsubsequent reduction.

The oxidizing bath necessary for forming the red masking imagecorresponds to the potassium ferricyanide bleaching baths usual forcolor development.

Example 1 100 g. of a red-sensitive silver bromide emulsion, whichcontains 1.2 g. of 3-(l'-hydroxy-2'-naphthoyl)-amino-4- methyloctadecylaminobenzene sulphonic acid or a water soluble salt thereof,such as the sodium-, potassiumor ammonium salt, and 0.3 g. of4-octadecylamino-3-aminobenzoic acid, is cast on to a support, and theresulting material is dried, exposed and processed in the followingbaths.

Color developer:

1 litre of water, g. of potassium carbonate, 2 g. of sodium sulphite,1.5 g. of potassium bromide, and 2.5 g. of p-diethylaminoanilinesulphate. Bleaching bath:

1 litre of water, g. of potassium ferricyanide, and 50 g. of potassiumbromide. Fixing bath:

1 litre of water and 200 g. of sodium thiosulphate.

A negative cyan image and a positive red correcting image are formed inthe processed layer.

The above diamine is obtained as follows:

3-nitro-4-octadecylamino-benzoic acid is produced in analogous manner asthe corresponding sulfonic acid derivative disclosed in Example 4 below,by replacing the Z-nitro-1-chlorobenzene-4-sulfonic acid by theequivalent amount of 4-chloro-3-nitro-benzoic acid. The aminated nitrocompound thereby formed is catalytically reduced in the presence ofRaney-nickel in met-hanolic solution.

There is obtained a reddish-grey powder decomposing at 203 C. whenheated.

The aforementioned diamino compound may be replaced by the equivalentamount of 3-arnino-4-dodecylamino-benzoic acid which is obtained inanalogous manner as the octadecylderivative. Point of decomposition 194C.

Example 2 A green-sensitive silver bromide emulsion, containing 1.2 g.of 1-(4-phenoxy-3-sulphophenyl)-3-heptadecyl pyrazolone per 100 g., iscast on to the red-sensitive layer referred to in Example 1. Anotherlayer which contains colloidal silver as yellow filter is cast thereon,followed by an optically non-sensitized silver bromide emulsioncontaining 1.5 g. of -(4-(stear0ylamino)-benzoyl acetarnino)-isophthalicacid per 100 g. After exposure and processing as in Example 1, anegative and complementary color image is formed, the cyan layer ofwhich also contains a positive red masking image.

Example 3 The multi-layer material cast as described in Example 2 ismodified by interchanging the red-sensitive and greensensitive layers.After the modified material has been exposed and processed in the sameway as in Example 2, practically no loss in sensitivity of thegreen-sensitive layer is found, although in this case the red mask isabove the green-sensitive layer.

Example 4 An optically non-sensitized silver bromide emulsion containing1.4 g. of 3-(p-anisoyl acetamino)-4-methyl octadecylaminobenzoic acidper 100 g. is cast on to a support and dried. A green-sensitized silverchloride emulsion containing 1.4 g. of 1-phenyl-3-heptadecyl-5-pyrazolone-3'-su1phonic acid per 100 g. is coated above the silverbromide emulsion. A red-sensitized silver chloride emulsion with 1.1 g.of l-hydroxy-Z-naphthoyl octadecyl amide-4-sulphonic acid, to whichthere have also been added 0.3 g. of 4-octadecyl amiuo-3-aminobenzenesulphonic acid, is cast above the green-sensitized silver chlorideemulsion. After exposure and processing of the resulting material as inExample 1, a complementary negative image is obtained, the yellowpartial image of which is in the lowermost layer, the magenta partialimage of which is in the middle layer and the cyan partial image ofwhich, together with a red correcting image, is in the uppermost layer.The last-mentioned diamine is produced as follows.

A mixture of:

26 g. of the sodium salt of 2-nitro-1-chlorobenzene-4- sulfonic acid,

26.4 g. of stearylamine,

9 g. of sodiumbicarbonate,

120 cc. of water,

100 cc. of butanol,

25 cc. of methanol is refluxed for hours. Thereafter about 150 cc. ofsolvent are distilled off, the residue is stirred with 250 cc. of hotmethanol, cooled and sucked oil. 30 g. of the2-nitrooctadecylanilinei-sulfonic acid (sodium salt) are dissolved in250 cc. of hot glacial acetic acid. The solution obtained is slowlyadded While stirring to 80 cc. of a solution which contains per 100 cc.of concentrated hydrochloric acid 60 g. of SnCI ZH O; the hot mixturehas added thereto 100 cc. of methanol and is stirred until the yellowcolor has disappeared. After cooling the compound formed is sucked oil,washed with methanol and dried at 60 C. Point of decomposition 247 C.The corresponding dodecylderivative has a point of decomposition of 258C.

The cyan couplers to be used for carrying out the process of the presentinvention are well known in the art. They are derivatives of phenol oru-naphthol having in ortho or para-position to the phenolic hydroxygroup a coupling function. Such phenolic compounds are eitherunsubstituted in the aforementioned positions or they are substituted bysubstituents which are split off during coupling with the oxidationproducts of the lCOlOI' forming developers such as primary aromaticamino compounds, such substituents being preferably sulfonic acid groupsor halogen atoms. Such couplers are preferred which are fast todiffusion, this property being for instance obtained by the presence ofhigher alkyl radicals having for instance 10 to 20 carbon atoms.Moreover these couplers may contain solubilizing groups such as sulfonicacid or carboxylic acid groups. Such couplers are for instance disclosedin US. Patents 2,184,849; 2,324,832; 2,357,395 and 2,366,324. Thecouplers and/or the diamines may also be incorporated in a waterpermeable, water insoluble solvent as described for instance in US.Patents 2,304,940 and 2,322,027 before they are added to the gelatinosilver halide emulsions.

As to the bleaching bath which is used for carrying out the process ofthe present invention it is preferred to use aqueous solutions of watersoluble ferricyanides, the pH value of said solutions being adjusted toabout 5 to 8 and the concentration to about 2 to 10 percent by weight.However, it is also possible to use other bleaching baths customary inthe art as for instance aqueous solutions of potassium bichromate.

I claim:

1. in the process for the production of a cyan photographic image with ared correcting mask, the steps of providing a silver halide emulsionlayer containing a cyan coupler selected from the class consisting ofphenols and naphthols that couple with the oxidation products of aprimary aromatic amine developer in a position orthoand parato thephenolic hydroxy group of the coupler to form a cyan dye, and a diamineof general formula where R represents an alkyl radical having at least 6carbon atoms and R represents a solubilizing group selected fromtheclass consisting of sulfonic acid and carboxylic acid groups, saidcoupler having a concentration of from 5 to 20 grams per kilogram ofemulsion and the diamine having a concentration of from 1 to 6 grams perkilogram of emulsion, exposing the emulsion to an optical image,developing the exposed emulsion with said developer to form a cyan imagein the illumina-ted portions of the emulsion, and subjecting thedeveloped emulsion to a bleaching operation with a bleaching bathselected from the class consisting of ferricyanide and chromatebleaching baths to remove the developed silver and thereby produce a redmasking dyestuft by reaction of said diamine with the residual couplerin the unillumina-ted portions of the emulsion.

2. The combination of claim 1, wherein the diamine is4-octadecylamino-3-aminobenzene sulphonic acid.

3. The combination of claim 1, wherein the diamiue is4octadecylamino-3-aminobenzoic acid.

4. The combination of claim 1, wherein the diamine is4-dodecylamino-3-arninobenzoic acid.

5. A photographic material comprising a silver halide emulsion layercontaining a cyan coupler selected from the class consisting of phenolsand naphthols that couple with the oxidation products of a primaryaromatic amine developer in a position orthoand parato the phenolichydroxy group of the coupler to form a cyan dye, and a diamine of thegeneral formula Where R represents an alkyl radical having at least 6carbon atoms and R represents a solubilizing group selected from theclass consisting of sulfonic acid and carboxylic acid groups, saidcoupler having a concentration of from S to 20 grams per kilogram ofemulsion and the diamine having a concentration of from 1 to 6 grams perkilogram of emulsion.

6. A photographic material according to claim 5 Wherein the diamine is4-octadecylamino-3-arninobenzene sulphonic acid.

7. A photographic material according to claim 5 wherein the diamine is4-octadecylamino-3-aminobenzoic acid.

8. A photographic material according to claim 5 wherein the diamine is4-dodecylamino-3-aminobenzoic acid.

References Cited in the file of this patent UNITED STATES PATENTS2,697,662 McQueen et a1. Dec. 21, 1954 10 2,805,158 Gauguin et al. Sept.3, 1957

1. IN THE PROCESS FOR THE PRODUCTION OF A CYAN PHOTOGRAPHIC IMAGE WITH ARED CORRECTING MASK, THE STEPS OF PROVIDING A SILVER HALIDE EMULSIONLAYER CONTAINING A CYAN COUPLER SELECTED FROM THE CLASS CONSISTING OFPHENOLS AND NAPHTOLS THAT COUPLE WITH THE OXIDATION PRODUCTS OF APRIMARY AROMATIC AMINE DEVELOPER IN A POSITION ORTHO- AND PARA- TO THEPHENOLIC HYDROXY GROUP OF THE COUPLER TO FORM A CYAN DYE, AND A DIAMINEOF GENERAL FORMULA